For a wide variety of applications, chairs and other types of seating furniture are nowadays provided with features which provide enhanced comfort to the person using the chair. For illustration, office-type chairs are commonly utilized in modern working environments to provide an occupant with a level of comfort while performing certain tasks that require a person to be in a seated position for an extended period of time. Similar features may be provided in other types of chairs to provide enhanced comfort to the person sitting on the chair.
One common configuration for such a chair includes a chair base assembly and a superstructure. The superstructure may include components which enable the user to recline or “tilt” the backrest of the chair. This basic chair configuration allows users to change their sitting position in the chair as desired, such that fatigue may be minimized during long sitting periods.
In recent years, chair designs have implemented a feature where the recline characteristics of a chair backrest may be altered. For illustration, the force applied by the chair backrest during a recline motion may be varied, so as to better accommodate the needs of different users. Adjusting elements may be provided on the chair which allow a user to manually adjust the force applied by the chair backrest. Alternatively or additionally, weight-responsive chairs may be provided with a mechanism in which the force applied by the chair backrest during a recline motion depends on a weight of a person sitting on a seat of the chair.
Such tilt mechanisms for weight-responsive chairs are typically designed with a central body fixed under the seat of the chair and are typically fixed exclusively on a gas column. The body of the tilt mechanism may therefore generally be visible, even if in some cases it may be fairly small. Such conventional tilt mechanisms for weight-responsive chairs are designed mainly to be used in the field of office chairs. Their overall dimensions and the fact that they are built to be fixed on a gas column complicate their application in other types of chairs. For illustration, when the seat of the chair is formed by an elastic membrane, it may be difficult or nearly impossible to use a conventional tilt mechanism which provides weight-dependent recline forces on such a chair.